Field device signals are signals provided by a field device, a sensor or a measuring device. Results of measurements, i. e., measured values, are packed or coded in a field device signal. Increasing use is today being made of digitally communicating devices in the area associated with instrumentation technology and process control systems, where sensors or actuators are connected to a controller or evaluator. These devices use field buses like the HART bus, PROFIBUS or Fieldbus Foundation to communicate with each other.
The devices involved are here sometimes difficult to wire, e.g., when obstacles such as river courses must be surmounted. In addition, existing wiring is difficult to modify once installed. In like manner, having to expand a measuring device can pose problems, since permanently installed bus systems most often predispose the installation sites of field devices. This holds true in particular when cabling with conduits. Wiring the evaluators and field devices can become a complicated and expensive proposition given complex geographic structures or long distances between field devices, measuring devices, sensors or actuators. In addition, wiring does not offer any flexibility with respect to modifications.